JP5386128B2 - Ozone oxidation promoter and cleaning method - Google Patents

Description

  The present invention relates to an ozone oxidation accelerator and a cleaning method.

Ozone has the strongest oxidizing power after fluorine. For this reason, conventionally, a method of processing (ozone processing) a processing object using this oxidizing power is used in various fields such as semiconductor cleaning, food cleaning (sterilization) or water purification.
In addition, ozone decomposes into oxygen and has an environmentally friendly aspect, so its use tends to expand.

By the way, in recent years, the market of cut vegetables and fruits (hereinafter referred to as “vegetables”) has been growing, and many of them are displayed at supermarkets and convenience stores.
These cut vegetables are more likely to be discarded due to the effect of cutting, because the freshness is likely to be lower than normal uncut vegetables. This is thought to be due to the fact that the bacteria propagate on the cut surfaces of vegetables and are susceptible to spoilage. Therefore, in the cut vegetables, improvement of freshness maintenance is desired from the viewpoint of profitability and the environment.

As a method for maintaining the freshness of the vegetables, methods using various freshness-keeping agents have been used so far. For example, a seasoning liquid for preventing discoloration of vegetables containing vinegar, ethyl alcohol and chitosan and a seasoning liquid for maintaining freshness have been proposed (see Patent Document 1).
However, the method of using a freshness-keeping agent as described in Patent Document 1 has a problem that an additive label is required because the compounding component (additive) remains in vegetables. Due to such problems, the method of using a freshness-keeping agent has been difficult to use for vegetable producers.
Moreover, in order to keep the freshness of the cut vegetables, the improvement of the packaging method and the storage method of the said vegetables is proposed. However, these methods are economically disadvantageous because they involve excessive costs including capital investment.

Conventionally, as a method of sterilizing and washing vegetables by ozone treatment, for example, there is a method of improving the sterilization effect by promoting the oxidation of ozone by using ozone with a compound having a specific dynamic surface tension. It has been proposed (see Patent Document 2).
Japanese Patent Laid-Open No. 06-125704 International Publication No. 2007/040260 Pamphlet

However, when the cut vegetables are washed by the ozone treatment described in Patent Document 2, the bactericidal effect on the vegetables has not been sufficient.
Moreover, in the cleaning by the ozone treatment, the cutting surface of the vegetables changes in color under the storage conditions for 3 days after the cleaning, or the vegetables change in color as a whole, and the effect of maintaining freshness is insufficient. .
This invention is made in view of the said situation, Comprising: It is a subject to provide the ozone oxidation promoter and washing | cleaning method with which the effect which was excellent in both sterilization of vegetables and the freshness maintenance is acquired by ozone treatment. To do.

As a result of intensive studies, the present inventors provide the following means in order to solve the above problems.
That is, the present invention relates to a compound (A) represented by the following general formula (1) and an acid (B) having a molecular weight of 100 or more and an acid dissociation index (pKa) in an aqueous solution at 25 ° C. of 3 or more. And an ozone oxidation promoter characterized by being mixed with water.

［式（１）中、Ｘ^１、Ｘ^２およびＸ^３は、それぞれ独立して下記一般式（２）で表される基又は水酸基を示す。ただし、Ｘ^１、Ｘ^２およびＸ^３のうちの少なくとも１つは下記一般式（２）で表される基である。］

[In Formula (1), X ¹ , X ² and X ³ each independently represent a group or a hydroxyl group represented by the following General Formula (2). However, at least one of X ¹ , X ² and X ³ is a group represented by the following general formula (2). ]

［式（２）中、Ｒは、炭素数１〜９の炭化水素基を示す。］

[In Formula (2), R shows a C1-C9 hydrocarbon group. ]

In the ozone oxidation promoter of the present invention, the acid (B) is preferably at least one selected from the group consisting of malic acid, succinic acid and gluconic acid.
In the ozone oxidation accelerator of the present invention, the compound (A) is preferably at least one selected from the group consisting of monoacetin, diacetin, triacetin, caprylic acid monoglycerin and capric acid monoglycerin.

  Moreover, it is preferable that the ozone oxidation promoter of this invention is used together with ozone at the washing | cleaning process, and is used by pH 3-5.5.

  Further, the cleaning method of the present invention is a method of supplying ozone into the water to be treated containing the processing object in the presence of the ozone oxidation accelerator of the present invention in the cleaning method of processing the processing object by ozone oxidation. It is characterized by having.

According to the ozone oxidation accelerator of the present invention, excellent effects of sterilizing vegetables and maintaining freshness can be obtained by using them during ozone treatment.
Moreover, according to the washing | cleaning method of this invention, the effect which was excellent in both sterilization of vegetables and the freshness maintenance is acquired.

≪Ozone oxidation accelerator≫
The ozone oxidation accelerator of the present invention is an acid having a compound (A) represented by the general formula (1), a molecular weight of 100 or more, and an acid dissociation index (pKa) in an aqueous solution at 25 ° C. of 3 or more. (B) and water are mixed.

[Compound (A)]
In the present invention, the compound (A) (hereinafter referred to as “component (A)”) is represented by the general formula (1).
By containing the component (A), ozone-containing gas can be made into fine bubbles (miniaturization) in the ozone treatment, and the effect of the present invention is improved.

In the formula (1), X ¹ , X ² and X ³ each independently represent a group or a hydroxyl group represented by the general formula (2).
In said formula (2), R shows a C1-C9 hydrocarbon group. The hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group may be linear, branched or cyclic, and may be saturated or unsaturated. Among these, R is preferably an aliphatic hydrocarbon group, more preferably a linear or branched chain, and particularly preferably a linear or branched alkyl group.
However, at least one of X ¹ , X ² and X ³ is a group represented by the following general formula (2).

  Examples of the component (A) include fatty acid esters of glycerin (glycerin monoester, glycerin diester, glycerin triester) in which R in the general formula (2) is an alkyl group having 1 to 4 carbon atoms; ) Fatty acid ester (glycerin monoester) of glycerin wherein R is an alkyl group having 5 to 9 carbon atoms.

  Specific examples of the component (A) include those shown in the following (x) to (z).

(X) One of X ¹ , X ² , and X ³ is glycerin monoacetate (monoacetin) in which R in the formula (2) is a methyl group and the other two are —OH.
(Y) ^{Two of} X ¹ , X ² and X ³ are glycerin diacetate (diacetin) in which R in the formula (2) is a methyl group and the other is —OH.
(Z) X ¹ , X ² , and X ³ are all glycerin triacetate (triacetin) in which R in the formula (2) is a methyl group.
Monoacetin and diacetin have structural isomers, and examples of the structural isomers of monoacetin include glycerin-1-acetate, glycerin-2-acetate, and glycerin-3-acetate. Examples of the structural isomer of diacetin include glycerin-1,3-diacetate and glycerin-1,2-diacetate.

Moreover, as (A) component, in addition to what is shown to said (x)-(z), for example, glycerol monopropionate, glycerol dipropionate, glycerol tripropionate; glycerol monobutyrate, glycerol dibutyrate Glyceryl tributyrate; monoglycerol pentanoate, monoglycerol caproate, monoglycerol heptylate, monoglycerol caprylate, monoglycerol 2-ethylhexanoate, monoglycerol pelargonate, monoglycerol caprate, etc.
Among these, structural isomers exist in glycerin monoester and glycerin diester, and in the same manner as shown in the above (x) to (z), the group represented by the formula (2) is represented by the formula ( Structural isomers bonded to X ¹ , X ² , X ³ ; X ¹ and X ² , X ¹ and X ³ , respectively, in 1).

  Among the above, as the component (A), monoacetin, diacetin, triacetin, monoglycerin caprylate, and caprin are used because they are water-soluble and have no use restrictions among food additives. It is preferably at least one selected from the group consisting of acid monoglycerin, particularly preferably at least one selected from the group consisting of monoacetin, diacetin and triacetin, most preferably triacetin.

As the component (A), it is preferable to use a component having no use restriction among food additives in consideration of food use such as fresh food. In addition, in ozone treatment, when bubbles of ozone-containing gas accumulate, there is a problem that the sterilizing effect is likely to be reduced due to overflow or a decrease in mechanical force applied to vegetables.
In view of these points, monoacetin, diacetin, or triacetin are particularly suitable because bubbles of ozone-containing gas hardly accumulate even when the amount of ozone aeration is increased. In addition, if any one of monoacetin, diacetin, triacetin, caprylic acid monoglycerin or capric acid monoglycerin is used, supply via an ejector without using various microbubble generators when refining ozone-containing gas The ozone-containing gas can be easily miniaturized by using a method or a diffuser tube. Thereby, not only the apparatus cost is reduced, but also the surface tension of the bubbles of the ozone-containing gas is lowered, the wettability to vegetables is increased, the ozone oxidation is promoted, and the cleaning property (bactericidal effect) can be expected to be improved.

  (A) A component can be used individually by 1 type or in combination of 2 or more types as appropriate.

[Acid (B)]
In the present invention, the acid (B) (hereinafter referred to as “component (B)”) has a molecular weight of 100 or more and an acid dissociation index (pKa) in an aqueous solution at 25 ° C. of 3 or more.
By containing the component (B), in the ozone treatment, the ozone oxidation is promoted together with the component (A) to improve the bactericidal effect, and the effect of maintaining freshness in the preservation of vegetables is improved.
Moreover, the usage-amount of ozone or the usage-amount of (A) component can also be reduced by using (B) component.

(B) The molecular weight of a component is 100 or more, 115 or more are preferable and 130-200 are more preferable. When the molecular weight is 100 or more, in addition to the bactericidal effect, both the reduction of the whole vegetable volume (harness) and discoloration of the vegetable (overall browning) due to storage are difficult to occur, and the effect of maintaining the freshness is achieved. improves.
This is because, during ozone treatment, acids with low molecular weight are expected to easily enter the vegetable cells, and the metabolic pathways in the cells are hindered by the effects of the acids that enter, so there is no tension. Moreover, discoloration (overall browning) of vegetables is considered to progress. The acid having a molecular weight of 100 or more is presumed to be particularly unlikely to cause such problems of elasticity and discoloration (overall browning) because the entry of vegetables into the cells is suppressed.

In the claims and in the present specification, “acid dissociation index (pKa)” means the negative common logarithm (−logKa) of the equilibrium constant (acid dissociation constant, Ka) of the dissociation reaction in which hydrogen ions are released from the acid. Represents.
In the case of a polyvalent acid, it is defined as the negative common logarithm (pKa ₁ ) of the equilibrium constant in the first-stage dissociation reaction. For example, phosphoric acid is a trivalent acid and has pKa ₁ , pKa ₂ , and pKa ₃ . In the present invention, the acid dissociation index (pKa) of phosphoric acid is pKa ₁ = 2.15 (25 ° C.).
The acid dissociation index (pKa) indicates a value (value obtained by measuring an aqueous solution of the component (B) at 25 ° C.) listed in the chemical manual basic edition revised edition 3 (published by Maruzen Co., Ltd.) edited by the Chemical Society of Japan. .
Moreover, acid dissociation index (pKa) prepared the aqueous solution which adjusted the ionic strength to 0.1 mol / L using the ultrapure water substituted by nitrogen at 25 degreeC, and this aqueous solution was made by Hiranuma Sangyo Co., Ltd. COM. -2500 and AT-510 manufactured by Kyoto Electronics Industry Co., Ltd. can be used for measurement.

The acid dissociation index (pKa) of the component (B) is 3 or more, preferably 3.2 or more, and more preferably 3.2 to 5. When the pKa is 3 or more, in addition to the bactericidal effect, the reduction of the whole vegetable volume (harness) and the discoloration (overall browning) of the vegetable due to storage are less likely to occur, and the effect of maintaining freshness is achieved. improves.
This shows that a small pKa value is likely to release hydrogen ions and is a strong acid. Therefore, even when the pH value is the same, the smaller the pKa value is, the more the cell is used. It is considered that the damage to the surface is large, so that the elasticity tends to be lowered and the discoloration (overall browning) of the vegetables is likely to proceed. In particular, in ozone treatment, the surface of vegetables is oxidized by ozone, so that defects of damage to the cell surface due to an acid having a small pKa value are likely to occur, and the acid enters the inside of the cells of vegetables. Presumed to be easy. If the pKa is 3 or more, the vegetables can be washed with almost no damage, and it is estimated that such problems of elasticity and discoloration (overall browning) are particularly unlikely to occur.
When pKa is 5 or less, the bactericidal effect is improved, and in particular, the browning of vegetables (redness of the cut surface) hardly occurs, and the effect of maintaining freshness is improved.

  In addition, in the present invention, during the ozone treatment, by adding the component (B) and lowering the pH, the cut surface of vegetables is less likely to be red, and the effect of maintaining freshness is improved.

Examples of the component (B) include malic acid, succinic acid, gluconic acid, malonic acid, tartaric acid, fumaric acid, glutamic acid, aspartic acid, and adipic acid.
Among them, the component (B) is at least one selected from the group consisting of malic acid, succinic acid, and gluconic acid, for the reason that the effect of maintaining freshness is improved in addition to the bactericidal effect. And is most preferably malic acid.

  (B) A component can be used individually by 1 type or in combination of 2 or more types as appropriate.

The ozone oxidation accelerator of the present invention may be used in the form of an aqueous solution obtained by mixing the component (A), the component (B), and water, and the component (A), ( B) The component and water may be used separately and mixed.
Further, when performing the ozone treatment, the aqueous solution of the component (A) and the component (B) may be mixed respectively, and the aqueous solution of the component (A) and the component (B) may be mixed respectively. Alternatively, the aqueous solution of the component (A) and the aqueous solution of the component (B) may be mixed respectively; the mixture of the component (A) and the component (B) and water may be mixed respectively. Good.

In the ozone oxidation accelerator of the present invention, the method of use is not particularly limited, and vegetables can be washed and sterilized by using in combination with ozone.
Among them, the ozone oxidation accelerator of the present invention is particularly suitable for sterilization and washing of vegetables such as lettuce, and is therefore used in combination with ozone in the washing process and at a pH of 3 to 5.5. Preferably there is.
As an ozone treatment method using the ozone oxidation accelerator of the present invention, for example, a cleaning method of the present invention to be described later is mentioned as a suitable method.

According to the ozone oxidation promoter of the present invention described above, excellent effects of sterilizing vegetables and maintaining freshness can be obtained by using them during ozone treatment. Moreover, according to the ozone oxidation promoter of the present invention, the surface of the vegetable can be sterilized while suppressing the damage to the vegetable due to the influence of the ingredients other than ozone, and the freshness of the vegetable can be maintained. .
The reason why such an effect is obtained is not clear, but is presumed as follows.

It is easily analogized that ozone has strong oxidizing power and high sterilizing power. However, since ozone is a gas, it is difficult to handle, and its use as dissolved ozone water is common in the cleaning field using ozone treatment. However, when it is used as ozone water, the ozone gas that could not be dissolved is discarded, so there is a lot of waste, and the dissolved ozone has a high reaction rate. In many cases, the amount of ozone water is more than necessary due to poor selectivity and permeability (entrance) to vegetables.
According to the study by the present inventors, when sterilized with 5 ppm by mass of ozone water, the vegetables after storage were extremely deteriorated (discoloration (overall browning) and disappearance of elasticity), and in addition to that, The bactericidal effect was not as good as that when sodium hypochlorite was used.
The ozone oxidation accelerator of the present invention is an acid having a compound (A) represented by the general formula (1), a molecular weight of 100 or more, and an acid dissociation index (pKa) in an aqueous solution at 25 ° C. of 3 or more. (B) and water are mixed.
In particular, by using the component (A), ozone can be kept in water as fine bubbles in a gaseous state, and the supply amount of ozone may be minimal, and the surface of vegetables due to the bubbles of ozone. With only sterilization and its cleaning effect, it is possible to improve both sterilization power and reduce damage to vegetables.
In particular, by using the component (B), the pH of the water to be treated is lowered, the ozone is stabilized, and the sterilizing power is further improved. In addition, since the component (B) has a molecular weight of 100 or more, entry into the vegetables is suppressed, and further, since the pKa is 3 or more, damage to the vegetables due to too strong acid strength is caused. It can be suppressed. As a result, the firmness is maintained, the cut surface is less likely to be red, and the effect of maintaining freshness is improved. According to the study by the present inventors, it has been confirmed that even when the pH of the water to be treated is 3.5 and the same conditions are used, when phosphoric acid having a pKa of less than 3 is used, the elasticity is lost.

The ozone oxidation accelerator of the present invention is suitable for use in a general food cleaning (sterilization) method using ozone treatment.
Moreover, it is preferable that the ozone oxidation promoter of this invention is used together with ozone in a washing | cleaning process, and is used by pH 3-5.5, In such a case, it is especially suitable for fresh food use.

According to the study by the present inventors, as a result of evaluating many kinds of vegetables, in cabbage, lettuce, etc., when the pH during the ozone treatment is 3 or more, discoloration of the vegetables during storage (overall browning) It was confirmed that it was more difficult to get up. Since the green color of vegetables becomes light at the beginning of storage, this is considered to be a result of the decomposition and destruction of chlorophyll. It was confirmed that this discoloration was remarkably suppressed when the pH was 3 or higher, and further suppressed when the pH was 3.5 or higher. Thus, especially in the condition of pH 3.5, it is excellent in the balance between the damage given to the vegetables and the bactericidal effect, and the initial state is maintained in the overall color tone, tension, and browning degree of the cut surface of the vegetables, Excellent freshness retention ability. In addition, the lower the pH, the more effective the sterilization effect because ozone stabilizes, and at the same time, the surface charges of both bacteria and ozone bubbles change. Therefore, it is considered that the bactericidal effect is improved by the fact that the bubbles are easily adsorbed by the bacteria.
On the other hand, if pH is 5.5 or less, both the bactericidal effect and the effect of maintaining freshness are improved. This is thought to be due to the fact that the sterilization effect is improved because ozone is more stabilized, and the decay of the vegetables is less likely to proceed, so that the discoloration (overall browning) of the vegetables is less likely to occur. .

In addition, the occurrence of red color on the cut surface often observed in lettuce stalks etc. (redness of the cut surface; generally referred to as “browning”) is reddening (browning) as the pH during ozone treatment is lowered. It is generally known that this browning phenomenon is an enzymatic reaction.
Such reddening (browning) is caused by adding acid (B) component during the ozone treatment to lower the pH, thereby causing phenylalanine ammonia lyase (PAL), which is the cause of browning of the cut surface, in the cut surface of cut vegetables. ) And polyphenol oxidase (PPO), and it is thought that the activity of these enzymes is reduced to reduce the activity.

≪Cleaning method≫
The cleaning method of the present invention is a cleaning method for processing an object to be treated by ozone oxidation (ozone treatment). In the presence of the ozone oxidation accelerator of the present invention, ozone is supplied to the water to be treated containing the object to be treated. It is the method which has the process to do.
Specific examples of the cleaning method include the following methods.

As such a cleaning method, for example, there is a method having a step of supplying (aeration) ozone into the water to be treated in which the vegetables to be treated are immersed in the presence of the ozone oxidation accelerator of the present invention. It is done.
The vegetables to be treated are not particularly limited and may be anything that is generally subjected to ozone treatment, such as bacteria, pigments, fats and oils, amines, proteins, humus, sludge, surfactants or Examples include organic substances such as agricultural chemicals, and vegetables and fruits to which they are attached.

The concentration of the ozone oxidation accelerator (the sum of the component (A) and the component (B)) in the water to be treated is preferably 0.001 to 5% by mass, and 0.01 to 1% by mass. % Is more preferred.
When the concentration of the ozone oxidation accelerator is 0.001% by mass or more, the effect of the present invention is high, and when it is 5% by mass or less, ozone and the ozone oxidation accelerator in the water to be treated react with each other. Consumption is suppressed, and as a result, the efficiency of ozone treatment is improved.
Ozone reacts with dissolved metals, chlorine, organic matter, etc. because of its strong oxidizing power, so the water to be treated is water with a low content of these impurities (high purity), for example, a resistivity of preferably 0.00001 MΩ. As described above, ultrapure water of 0.001 MΩ or more, more preferably 1 MΩ or more is more preferable because it is advantageous for the reaction.

The mixing ratio of the component (A) and the component (B) in the water to be treated is preferably (A) / (B) = 1/1000 to 500/1 in terms of mass ratio, and 1/10 to 10/1. It is more preferable that
When the ratio of the component (A) to the component (B) is equal to or greater than the lower limit, the bactericidal effect due to the refinement of bubbles is further improved. On the other hand, if it is not more than the upper limit value, a synergistic effect of improving sterilizing power can be obtained. In particular, the decrease in the volume (harness) of the whole vegetables and the discoloration (overall browning) of the vegetables are less likely to occur, and the effect of maintaining freshness is improved. This is thought to be because the concentration of the component (B) is kept moderate and the entry of the component (B) into the vegetables is suppressed.

During the ozone treatment, the ozone oxidation accelerator of the present invention is preferably used at a pH of 3 to 5.5, more preferably at a pH of 3.5 to 5, and a pH of 3.5. Most preferred.
When the pH is 3 or more, in addition to the bactericidal effect, the decrease in the volume (harness) of the whole vegetables and the discoloration (overall browning) of the vegetables are particularly difficult to occur, and the effect of maintaining freshness is achieved. improves. In addition, browning (redness of the cut surface) hardly occurs, and the quality of the vegetables themselves is improved. When the pH is 5.5 or less, a sufficient bactericidal effect is obtained, discoloration (overall browning) of vegetables hardly occurs, and the effect of maintaining freshness is improved. In addition, the effect of using the component (B) can be obtained better.

The pH here means the pH of the water to be treated containing the component (A) and the component (B), and the pH value of the water to be treated itself measured using a hydrogen electrode or the like at 25 ° C. Show.
The pH of the water to be treated can be adjusted by using an alkali agent such as sodium hydroxide or potassium hydroxide; an acid such as hydrochloric acid or sulfuric acid.

  In the case of ozone treatment, in addition to the component (A) and the component (B), the water to be treated is used as a component other than the component (A) and for stabilizing the product and imparting functions as long as the ozone oxidation reaction is not inhibited. In addition, various surfactants, fragrances, enzymes, fluorescent agents, thickeners, dispersants, inorganic salts, alcohols, saccharides and the like may be contained.

For aeration of ozone, for example, water to be treated containing an ozone oxidation accelerator and an object to be treated is contained in a container, and the gas to be treated contains at least ozone (referred to as “ozone-containing gas” or “aeration gas”). ). Moreover, you may add an ozone oxidation promoter to to-be-processed water, supplying aeration gas in to-be-processed water.
Further, in the step of supplying ozone (aeration) into the water to be treated, it is possible to use a stirring device or the like in order to agitate the water to be treated when aeration is performed.
As the container (treatment container) that contains the treated water and performs aeration, since the oxidizing power of ozone is strong, the material of the surface in contact with the treated water is glass, Teflon (registered trademark), titanium, ozone treatment (high Aluminum or stainless steel having a strong oxide film formed by ozone at a concentration of ozone is preferred.
When using a material such as nitrile rubber or urethane having low resistance to ozone, it is necessary to pay sufficient attention to deterioration of the processing container.

As the aeration gas, generated ozone may be used as it is, or may be supplied after diluted with a dilution gas.
The generation method of ozone is not particularly limited, and examples thereof include a method of irradiating oxygen with high energy light such as an electron beam, radiation, and ultraviolet rays; a chemical method, an electrolytic method, a discharge method, and the like. Industrially, the silent discharge method is often used because of generation cost and generation amount.
Commercially available ozone generators can be used to generate ozone. For example, YGR-50 (trade name) manufactured by Lacey Co., Ltd. and ED-OG-PSA1 (trade name) manufactured by Ecodesign Co., Ltd. as low-concentration ozone generators. OZSD-3000A (trade name) manufactured by Sugawara Jitsugyo Co., Ltd. is commercially available.
Ozone is preferably used immediately after preparation because it has autodegradability.

As a dilution gas used for dilution of ozone, a gas inert to ozone or poor in reactivity is preferable, and examples thereof include helium, argon, carbon dioxide, oxygen, air, and nitrogen.
The ozone concentration in the aerated gas (ozone-containing gas) is not particularly limited, but the operability and handling of the worker are improved, and deterioration due to oxidation of vegetables is further suppressed, and the freshness maintaining effect is improved. Therefore, it is preferably 10,000 ppm volume% or less, more preferably 5000 ppm volume% or less, and even more preferably 1000 ppm volume% or less.
On the other hand, the lower limit is not particularly limited, and is preferably 1 ppm by volume or more, more preferably 10 ppm by volume or more, considering ozone treatment efficiency.

A method of aeration of aeration gas into the water to be treated is not particularly limited. For example, a method of controlling the flow rate of the aeration gas with a mass flow controller and the like and supplying it to the water to be treated through an ejector; diffuser plate, diffuser cylinder, diffuser A conventionally used method can be used.
The treatment temperature at the time of aeration (that is, the temperature of water to be treated) is not particularly limited and is preferably 5 to 30 ° C. If it is 5 ° C. or higher, the solubility of ozone in the water to be treated is increased, and if it is 30 ° C. or lower, the self-decomposition of ozone is less likely to occur and the sterilization efficiency is improved. The treatment temperature is more preferably in the range of 10 to 25 ° C. because damage to vegetables is further suppressed.
The treatment time for aeration (aeration time) is not particularly limited, taking into consideration the treatment purpose, the ease of decomposition of the treatment object, the concentration of the treatment object in the treated water, the temperature, the treatment volume, etc. Can be set. (B) Since the approach to vegetables, such as a component, is suppressed more, it is preferable that processing time shall normally be 30 minutes or less, and it is more preferable to set it as 15 minutes or less.

In this step, an accelerated oxidation treatment (AOP) may be performed in order to promptly proceed with bleaching or decomposition of a hardly decomposable substance in combination with the aeration treatment.
AOP generates ozone radicals with high oxidizing power by actively decomposing ozone, thereby further promoting the oxidation reaction. As means for actively decomposing ozone, ultraviolet irradiation, H ₂ O ₂ , addition of an inorganic catalyst, and the like are generally used.
Moreover, after this process, the rinse for washing away the component etc. which adsorb | sucked to vegetables as needed, drying, etc. can be performed suitably.

  According to the cleaning method of the present invention described above, excellent effects can be obtained in both sterilization of vegetables and preservation of freshness.

  Hereinafter, the present invention will be described in more detail using examples, but the present invention is not limited to these examples.

(Measurement of pH)
In the following examples, the pH is measured by directly inserting the pH electrode into a solution of about 25 ° C. to be measured using a pH meter (product name: SevenEasy, manufactured by METTLER TOLEDO) Measured by reading.

<Preparation of ozone oxidation accelerator>
40 L of tap water was stored in a washing machine (product name: CW-C30A1, manufactured by Mitsubishi Electric; 2-tank washing machine).
Next, the component (A) and the component (B) were dissolved so as to have the blending amounts shown in Tables 1 and 2 (ppm by mass; converted to pure content).
Next, the pH is adjusted using a 5N-NaOH aqueous solution or a 5N-HCl aqueous solution so that the value of “pH during ozone treatment” shown in Tables 1 and 2 is prepared, and an ozone oxidation accelerator of each example is prepared. did.

The raw materials used in this example are as follows.
In addition, the value of pKa ₁ in acid (B) and acid (B ′) is the value (25 ° C. aqueous solution) listed in the Chemical Handbook Basic Edition 3rd edition edited by The Chemical Society of Japan (published by Maruzen Co., Ltd.). Measured value).

Compound (A)
Triacetin: Reagent manufactured by Kanto Chemical Co., Inc., molecular weight 218.2.
Monoacetin: Reagent manufactured by Kanto Chemical Co., Inc., molecular weight 134.1.
Caprylic acid monoglycerin: a reagent manufactured by Riken Vitamin Co., Ltd., molecular weight 218.3.
Monoglycerin caprate: a reagent manufactured by Riken Vitamin Co., Ltd., molecular weight 246.3.

・ Acid (B)
Malic acid: reagent manufactured by Kanto Chemical Co., Inc., molecular weight 134.1, pKa ₁ = 3.2.
Gluconic acid: reagent manufactured by Kanto Chemical Co., Inc., molecular weight 196.2, pKa ₁ = 3.7.
Succinic acid: reagent manufactured by Kanto Chemical Co., Inc., molecular weight 118.1, pKa ₁ = 4.0.

Acid (B ′): Comparative component of acid (B) Phosphoric acid: Reagent manufactured by Kanto Chemical Co., Inc., molecular weight 98.0, pKa ₁ = 2.2.
Pyrophosphate: reagent manufactured by Kanto Chemical Co., Inc., molecular weight 178.0, pKa ₁ = 0.8.
Acetic acid: reagent manufactured by Kanto Chemical Co., Inc., molecular weight 60.1, pKa ₁ = 4.6.
Citric acid: reagent manufactured by Kanto Chemical Co., Ltd., molecular weight 192.1, pKa ₁ = 2.9.

5N-NaOH aqueous solution: Reagent (Cat. No. 37844-08) manufactured by Kanto Chemical Co., Inc.
5N-HCl aqueous solution: Reagent (Cat. No. 18589-08) manufactured by Kanto Chemical Co., Inc.

<Cleaning by ozone treatment>
Vegetables (lettuce) were sterilized and washed according to the following flowchart with reference to ozone treatment in a general fresh food factory.
(Pre-washing) → (Sterilization / washing) → (First rinse) → (Second rinse) → (Dehydration)

Pre-washing was carried out by putting 500 g of vegetables (lettuce) in an electric bucket (product name: N-Bk2, manufactured by Matsushita Electric Industrial Co., Ltd.) in which 7 L of tap water was stored for 2 minutes.
For sterilization and washing, an ozone oxidation accelerator is prepared in advance as described above using a washing machine (product name: CW-C30A1, manufactured by Mitsubishi Electric; 2-tank washing machine) in which 40 L of tap water is stored. Vegetables (lettuce) were put there, and it was performed by stirring for 5 to 10 minutes under the ozone aeration conditions described later.
The first rinsing was performed by storing 40 L of tap water in the 2-tank washing machine (product name: CW-C30A1, manufactured by Mitsubishi Electric Corporation) and stirring for 1 minute.
In the second rinsing, 20 L of water was stored in a bucket, and the mixture was lightly stirred using a sterilized stainless steel (15 cm diameter, 2 mm mesh) colander.
The dehydration was performed for 1 minute in the dewatering tank of the two-tank washing machine (product name: CW-C30A1, manufactured by Mitsubishi Electric).

In addition, the movement of the vegetables (lettuce) between each operation was performed using the stainless steel colander sterilized with ethanol.
In addition, the processing method used as the standard (industry standard) in [Evaluation of sterilizing power] described below is the following flow chart in which the operation of (sterilization / washing) is used for sterilization of fresh food in the food industry. The same procedure was followed except that the operation was changed to a 5-minute treatment with 200 ppm of Na chlorate.
Moreover, in Comparative Example 8, ozone was not used and only air was aerated.

(Ozone aeration conditions)
The method of sterilization / cleaning in the above <cleaning by ozone treatment> is the ozone treatment device shown in FIG. 1 made by using a washing machine (product name: CW-C30A1, manufactured by Mitsubishi Electric; 2-tank washing machine). Used.
The ozone treatment apparatus 1 includes a two-tank washing machine 10 including a washing tub 11 and a dehydration tub 12, an ozone-containing gas supply device 20, and an ozone oxidation accelerator sucked from the washing tub 11 to supply an ozone-containing gas. And a circulation path 30 that circulates while ozone-containing gas is supplied from the apparatus 20.
The washing machine 10 has a pulsator 13 at the bottom of the washing tub 11.
The ozone-containing gas supply device 20 includes an air cylinder 21 that sends out air, a regulator 22 that controls the flow rate (ozone concentration) of air, and an ozone monitor (product name: EG-600) that generates ozone in the sent air. Ozone Generator 23 (product name: OZSD-3000A, manufactured by Ebara Jitsugyo Co., Ltd.) and a mass flow controller 24 (product name: MODEL 5100, Coflock) for controlling the flow rate of ozone-containing gas. (Made by Co., Ltd.).
The circulation path 30 includes paths 31, 32, and 33 made of vinyl chloride, and SUS304 is used as a material for a joint (not shown). Between the path 31 and the path 32, a circulation pump 34 (product name: M20NED04S type, manufactured by Nikuni Co., Ltd.) is provided. In addition, an ejector 35 made of vinyl chloride is provided between the path 32 and the path 33 to control the supply of ozone-containing gas to the circulating ozone oxidation accelerator. The end of the path 31 opposite to the pump 34 is installed near the bottom of the washing tub 11, and the end is provided with a 1 mm diameter mesh made of Teflon (registered trademark) to prevent vegetable inhalation. 36 is provided.

In the ozone treatment of this example, the circulation of the ozone oxidation accelerator was performed at 10 L / min. The flow rate was as follows.
Ozone was generated in the air sent from the air cylinder 21 so that the ozone concentration was 5000 ppm by volume. The ozone concentration was controlled by a regulator 22.
Supply of the ozone-containing gas to the circulating ozone oxidation accelerator is performed via the ejector 35, and the flow rate of the ozone-containing gas is 0.4 L / min. The ozone-containing gas was supplied (aerated) to the ozone oxidation accelerator.

<Evaluation>
Using the vegetables (lettuce) after drying in the above <cleaning by ozone treatment>, the evaluation of the bactericidal power and the effect of maintaining the freshness shown below were performed.

[Evaluation of sterilizing power]
The sterilizing power was evaluated by examining the number of bacteria.
In the inspection of the number of bacteria, the buffer containing peptone contained 3.56 g of potassium dihydrogen phosphate, 18.2 g of disodium hydrogen phosphate dodecahydrate, 4.3 g of sodium chloride and 1.0 g of peptone 1 What was melt | dissolved in the liter and neutralized to pH 7.0 was used.
The number of bacteria was examined as follows.
25 g of lettuce before and after washing by the ozone treatment was added to 225 mL of peptone-containing buffer solution, and the mixture was pulverized by using a stomacher bag with a filter to prepare a suspension. This suspension was diluted stepwise and poured on an SCD agar medium (Nissui Pharmaceutical Co., Ltd.).
This operation was repeated three times per sample, and after culturing at 37 ° C. for 24 hours, the number of viable bacteria was determined as the number of bacteria per 1 g of vegetables by counting the colonies.
The bactericidal power is based on the ratio of the number of bacteria at the time of treatment in each example with respect to the number of bacteria at the time of treatment with 200 ppm of sodium hypochlorite, which is an industry standard. Is equivalent to less than 10 ^{× 0.7} ). The results are shown in the table. In the table, values in parentheses indicate the ratio (multiple).

[Evaluation of freshness retention effect]
The freshness retention effect was evaluated by a storage test.
In the storage test, about 300 g of lettuce before and after washing with the ozone treatment is put in a plastic bag with a zip, and stored at 10 ° C. for 3 days using a UKS-3600HC biomulti cooler (trade name) manufactured by Japan Freezer Co., Ltd. did.
The freshness retention effect is 5 points before washing by ozone treatment for 3 items of lettuce firmness, browning (mainly reddish cut surface), and discoloration (overall browning), after storage for 3 days The state of was evaluated in five stages based on the following evaluation criteria.
Regarding the above three items, three or more points were evaluated as ◯ (pass). In addition, the total score of these three items was 10 (or better). The results are shown in the table. In the table, the value in () indicates the score.

Hari: The volume of lettuce in the zip after storage for 3 days was determined visually.
5 points: almost no decrease in volume.
4 points: There was almost no decrease in volume, but the vegetables were slightly soft.
3 points: The rate of volume reduction was less than 20%.
Two points: The rate of volume reduction was 20% or more.
1 point: The rate of volume reduction was 50% or more.

Browning (mainly red color of the cut surface): The presence or absence of redness was evaluated mainly on the cut surface of lettuce after storage for 3 days.
5 points: No red color was present throughout.
4 points: Redness was observed in less than 20% vegetable pieces.
3 points: Redness was observed in less than 50% vegetable pieces.
2 points: Redness was observed in 50% or more pieces of vegetables.
1 point: A dark red color was observed in almost all vegetable pieces.

Discoloration (overall browning): The color tone of the whole lettuce after storage for 3 days was evaluated under a fluorescent lamp.
5 points: The original color tone was maintained as a whole.
4 points: Slight dullness was observed overall.
3 points: Some vegetable pieces had turned brown.
2 points: Almost all of the vegetable pieces turned pale brown.
1 point: Almost all of the vegetable pieces turned brown.

  From the results of Tables 1 and 2, according to the ozone oxidation accelerators of Examples 1 to 11 and the cleaning method using the same according to the present invention, excellent effects of both sterilization of vegetables and preservation of freshness can be obtained. I was able to confirm.

On the other hand, the ozone oxidation promoters of Comparative Examples 1 to 4 using the comparative component (B ′) of the acid (B) and the cleaning method using the same have a low freshness-keeping effect, and the storage and the discoloration (overall) (Browning) was confirmed to be particularly bad.
In particular, in Comparative Example 1 (phosphoric acid), Comparative Example 2 (pyrophosphoric acid), and Comparative Example 4 (citric acid), a phenomenon in which vegetables were significantly softened by storage was observed, and it was confirmed that they had lost elasticity. .
Further, in Comparative Example 1 (phosphoric acid) and Comparative Example 3 (acetic acid), it was confirmed that discoloration (overall browning) after storage was particularly bad.

It is a schematic diagram which shows the ozone treatment apparatus used for the present Example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Ozone processing apparatus 10 Washing machine 11 Washing tank 12 Dehydration tank 13 Separator 20 Ozone containing gas supply apparatus 21 Air cylinder 22 Regulator 23 Ozone generator 24 Mass flow controller 30 Circulation path 31 Path 32 Path 33 Path 34 Pump 35 Ejector 36 Strainer

Claims (5)

Compound (A) represented by the following general formula (1),
An acid (B) having a molecular weight of 100 or more and an acid dissociation index (pKa) in an aqueous solution at 25 ° C. of 3 or more;
An ozone oxidation promoter characterized by mixing with water.

[In Formula (1), X ¹ , X ² and X ³ each independently represent a group or a hydroxyl group represented by the following General Formula (2). However, at least one of X ¹ , X ² and X ³ is a group represented by the following general formula (2). ]

[In Formula (2), R shows a C1-C9 hydrocarbon group. ]   The ozone oxidation promoter according to claim 1, wherein the acid (B) is at least one selected from the group consisting of malic acid, succinic acid and gluconic acid.   The ozone oxidation promoter according to claim 1 or 2, wherein the compound (A) is at least one selected from the group consisting of monoacetin, diacetin, triacetin, caprylic acid monoglycerol and capric acid monoglycerol.   The ozone oxidation promoter according to any one of claims 1 to 3, which is used in combination with ozone in a washing step and used at a pH of 3 to 5.5. In a cleaning method for processing a processing object by ozone oxidation,
A cleaning method comprising a step of supplying ozone into water to be treated containing an object to be treated in the presence of the ozone oxidation accelerator according to claim 1.

Images